The rise of cloud computing just might be themost important thing happening in information technologytoday. While not everything will move into the cloud, it's fair to say that nearly every organization will usethis new approach in some way. Given this reality, cloud computing has the potential tochange manyaspects of our world.

For users of geographic information system (GIS) technology, the cloud opens a number of newpossibilities. But what are those possibilities, and why might they be better than what you're doing now?In fact, why should you

care about cloud computing at all?

The goal of this paper is to answer these questions. After a quick introduction to cloud computing, we'lllook at some concrete examples by exploring what Esri is doing today to bring GIS to the cloud.

CLOUD APPLICATIONS

AND CLOUD PLATFORMS

The phrase "cloud computing" means different things to different people. This discussion focuses entirelyon public clouds, in which code and data live in Internet-accessible data centers owned by Amazon,Microsoft, Google, and others.

In this context, it's useful to distinguish between two broad categories:cloud applications and cloud platforms. Figure 1 illustrates this idea.

Figure1: Cloud applications are accessed by users, while cloud platforms are used

by developers.

Like the applications that run in your data center (sometimes referred to ason-premises

applications),cloud applications have users. The big difference is that unlike on-premises applications, cloudapplications run in a shared data centerthat’s accessed via the Internet. This application style issometimes calledSoftware as a Service

(SaaS),and it gets more common every day. Some visibleexamples of SaaS applications include the customer relationship management provided by Salesforce.comCRM, the document creation services provided by Google Apps, and the business-oriented email serviceoffered by Microsoft Exchange Online. Going forward, more and more organizations are likely to rely oncloud applications for a range of business functions.

As Figure 1 shows, however, applications aren't the only cloud computing option. It's also possible tocreate platforms that run in Internet-accessible data centers rather than inside your own firewall. Thesecloud platforms can run applications, store data, and provide other useful services. And while oneimportant role of cloud platforms is to support cloud applications, cloud platforms themselves are ofinterest to developers rather than end users, as the figure shows. Several providers offer public

cloudplatforms today, but the technology was pioneered by Amazon. Their offering, called Amazon WebServices (AWS), remains a leader in this space, and it's worth a closer look.

virtual machines (VMs)through its Elastic Compute Cloud (EC2) service.Developers can request a VM (also called an EC2instance) through the AWS Web site, install any softwarethey like in it, then begin usingit. The VM is actually located at an Amazon data center, and its creator ischarged for each hour the VM runs. This approach is commonly calledInfrastructure as a Service

(IaaS),since it provides a basic foundation for running software.

The creator of a VM specifies anAmazon Machine Image (AMI) from which this instance should becreated. An AMI can be based on either Linux or Windows Server, and many different AMIs are available.As Figure 2 suggests, for example, some AMIs contain preconfigured database management systems,while others contain Web servers and other supporting software for applications.

To store data, AWS provides several different options. The most commonly used choice today is theSimple Storage Service (S3), which stores unstructured data (known as

binary large objects, or blobs). S3also provides storage for Elastic Block Store (EBS) volumes, which allow persisting the contents of an EC2VM's file system. Another AWS storage option is the Relational

Database Service (RDS), giving developersmanaged relational storage based on MySQL. And although they're not shown in the figure, AWS providesother choices as well, including support for storing very large structured, non-relational datasets.

The basics

of cloud technology aren't hard to understand. Yet by itself, this technology has no value—thevalue comes from how it's used. One important example of this is providing GIS services in the cloud, asdescribed next.

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GIS AND CLOUD COMPUTING: EXAMPLES FROM

ESRI

Esri uses the cloud today in several different ways. The currently available options include the following:

The ability to deploy ArcGIS Server on Amazon Web Services.

ArcGIS.com, a Web site offering tools and shared data for GIS applications.

ArcLogistics, a cloud application for optimizing routing, such as for delivery vehicles.

Business Analyst Online, a cloud application for geographic analysis of demographic, consumer,business, and other data.

These examplesillustratehow cloud computing can make life better for GIS developers and users. Eachone is worth a closer look.

ARCGIS SERVER ON AMAZON EC2

ArcGIS Server is a platform for delivering GIS services to software on other systems. These capabilities areexposed as RESTful services, via SOAP, and in other ways, and they can be consumed by clients writtenusing various technologies, including JavaScript, Adobe Flex, and Microsoft Silverlight.

Today, customers typically deploy ArcGIS Server on a computer running in their own data center. It's alsopossible, however, to deploy ArcGIS Server in the cloud using AWS. As Figure 3 shows, ArcGIS Server itselfcan run in an EC2 VM running Windows, while a relational database holding GIS data runs in a second VM.

Deploying ArcGIS Server on AWS provides an alternative to deploying it solely in your own data center.But why would anybody do this? What are the advantages of choosing this option? There are severalpossible answers, including the following:

Easier deployment: Esri provides a preconfigured AMI containing ArcGIS Server. Rather thaninstall and configure the product on a machine in your data center, you can just create an EC2VM from this AMI.

Faster deployment: In many organizations, making a server machine available to run newsoftware requires following a multi-step process, one that can take weeks or more. With AWS, bycontrast, anybody with a valid credit card can get an EC2 VM deployed in a few minutes. Ifgetting ArcGIS Server—and the application that uses it—up and running quickly is important,using the AWS option can make sense.

Lower cost: As mentioned earlier, AWS charges customers for each hour a VM is running.Depending on usage and costs in your own datacenter, running ArcGIS Server on AWS might bea less expensive option. This is especially true for applications with elastic (i.e., widely varying)demand. If, say, an application typically uses a single instance of ArcGIS Server, but needs teninstances for occasional peak loads, the AWS pay-as-you-go model lets you pay for this higherusage only when you need it.

Broad availability: Because software running on AWS can be accessed by anybody with anInternet connection, GIS services exposed by ArcGIS Server in an EC2 VM can be broadlyavailable. While this raises the security bar, it can be an attractive approach for providing somekinds of information.

Better performance: ArcGIS Server allows running various kinds of analysis on GIS data. If you'recreating an application that performs complex data analysis, you might choose to deploymultiple instances of ArcGIS Server in multiple EC2 VMs, then use all of them in parallel to workon the same data. Applications running on AWS also have access to large amounts of bandwidth,which can significantly improve performance in some cases.

Simpler development and testing: Because the AWS environment can be essentially identical toan on-premises Windows environment, a development team can build and test an ArcGIS Serverapplication in the cloud, then deploy it either in the cloud or on premises. Given that creating(and paying for) EC2 VMs can be more flexible than creating the same environment in your owndata center, this can make the development process easier.

Running ArcGIS Server in the cloud isn't always the right solution, of course. In many organizations, forinstance, storing sensitive information outside the firewall is frowned upon. Still, this alternativedeployment approach can sometimes be the best option.

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ARCGIS.COM

Using the cloud to share GIS data and applications is an attractive idea. ArcGIS.com, run by Esri, provides agood example of this. Figure 4 shows the site's home screen.

Figure 4: ArcGIS.com is a Web site providing access to GIS data and

applications.

As this screen shot suggests, ArcGIS.com provides a number of services, including the following:

Storage of publicly available maps and other GIS information. (Esri provides some of this data,including things such as layers and basemaps, but users of the site also contribute.)

Esri-created applications for examining and working with the site's information, such as tools forcreating maps.

A central site for finding and accessing GIS applications that use the data on ArcGIS.com,including applications that run on computers in non-Esri

data centers.

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Figure 5 shows the main components of ArcGIS.com.

Figure 5: Run by Esri, ArcGIS.com provides Internet-accessible GIS data and applications that can beused by many clients.

ArcGIS.com provides tools designed to let non-expert users create and work with maps. As Figure 5shows, those tools include a JavaScript viewer for browsing GIS data, along with the Silverlight-basedArcGIS Explorer Online, a more powerful tool for creating and working with maps. Both of these toolsaccess data via services exposed by ArcGIS Server. These services can also be accessed through other Esri-provided clients, including ArcGIS Explorer (the more functional on-premises version of ArcGIS ExplorerOnline), ArcGIS Desktop, and mobile devices such as the iPhone. As mentioned earlier, it's also possiblefornon-Esri

applications to access this data through the services exposed by ArcGIS Server.

As the figure shows, Esri has built ArcGIS.com today on Amazon Web Services. The site's logic, includingits user interface and ArcGIS Server, runs in EC2 VMs, while the GIS data is stored as blobs in S3. Thisdependence isn't visible to the site's users, of course—they just see the user interface and other servicesthat the site offers—but it's another example of how Esri is using cloud technology.

One final question worth addressing is this: Is ArcGIS.com a Web site or is it a cloud application? The realanswer is that it's both. Some Web sites, such as those that provide only static pages to their users, clearlydon't qualify as cloud applications. Others, though, especially sites offering useful tools such asArcGIS.com, just as clearly do fit into the category of cloud applications. While not every Web site is acloud application, it's probably fair to say that every cloud application can be seen as a Web site.

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ARCLOGISTICS

Think about an organization that maintains a fleet of vehicles. Maybe it's a large delivery company thatsends out hundreds of trucks aday, for example, or a home healthcare service that must coordinate pick-ups and drop-offs of a dozen people. While the details differ, these firms face a similar problem: Theyneed to route their vehicles as efficiently as possible. Add in other important

variables—vehicle capacity,the times that customers can accept delivery, and more—and the problem gets even harder.

The goal of ArcLogistics is to help them solve this problem. This cloud application lets a user enter thenumber of vehicles together with

the stops they must make, then get back optimized routing for thesevehicles. Figure 6 illustrates the application's components.

Figure 6: ArcLogistics is a cloudapplication

for creating optimized routes.

Once again, this application is built on Amazon

Web Services, with logic running in an EC2 VM and datastored in S3. (No sensitive client data is stored in the cloud, however—it's sent in, used for computation,and deleted, which minimizes security issues.) Note that the ArcLogistics client isn't a Web

browser.Instead, it's a custom Windows application built using Windows Presentation Foundation. And althoughit's not shown in the figure, the ArcLogistics server component is actually built using ArcGIS Server.

Esri

also provides a desktop version of ArcLogistics. The application's cloud incarnation has somesignificant advantages over its on-premises predecessor, however. Those advantages include thefollowing:

Lower cost of entry: Rather than the fixed price of the desktop version, which is high enough tobe feasible only for larger organizations, ArcLogistics in the cloud is priced based on the numberof vehicles a customer has. This makes getting started cheaper, and it also opens the applicationto smaller organizations with only a few vehicles.

Try before you buy: Rather than buy an on-premises application, install it, learn how to use it,and only then determine whether it actually has business value, ArcLogistics in the cloud lets apotential customer try the service on a small scale. The customer can then adopt (and pay for)the application only if it delivers significant value.

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No on-premises data or software updates: To do its job, ArcLogistics needs an up-to-date pictureof the geography over which it's finding optimized routes. Since the world changes, this databasemust be updated periodically. With the desktop version, each customer must regularly installupdated data sent out by Esri. With ArcLogistics in the cloud, this is no longer required. Instead,all customers rely on a single shareddatabase that's updated centrally. Everybody always hascurrent information with no need to install updates themselves.

And because there's just onecopy of the application, Esri can also update this code centrally, making new featuresimmediately available to all users.

Better customer support: Since all customers of ArcLogistics in the cloud are using the same codewith the same underlying data, the application's support people can do a better job. With thedesktop version, different customers might havedifferent releases, older data, or both, makingsupport significantly more challenging.

Better performance: Computing optimized routes is CPU-intensive work. Doing this on a cloudplatform such as AWS lets ArcLogistics create as many VMs as needed for whatever the currentcustomer demand might be. It also lets customers avoid dedicating their own compute resourcesto this task.

ArcLogistics is a good example of an application that probably makes more sense in the cloud than it doesin your data center. It's

compute

intensive, relies on a large and changing database, and doesn't need tostore sensitive information outside your firewall. It's also a good example of how cloud computing canimprove our lives.

BUSINESS ANALYST ONLINE

Suppose it's your job to choose a new location for a children's clothing store. To make a good decision,you'd like to know how many families with young children live within, say, a 20-minute drive of eachpotential location, along with their median income. Answering questions like these is the purpose ofBusiness Analyst Online. By providing demographic information and other data, along with tools forworking with that data, this cloud application can help business owners, planners, realtors, and othersmake better decisions. Figure 7

shows its main components.

Figure 7: Business Analyst Online is a cloud application for working with demographic data, consumerdata, and other information.

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As the figure shows, Business Analyst Online can be accessed from an ordinary Web browser. Theapplication also exposes a Web services interface that lets it be used by other clients. Esri provides aniPhone app, for example, and third parties can also access these services. Notice that this cloudapplication isn't built on Amazon Web Services or another cloud platform. Instead, it runs in Esri's ownInternet-accessible data centers. While cloud platforms can be quite useful, there's no requirement that acloud application be built on one.

Like ArcLogistics, this application also comes in on-premisesversions, including both a desktop and aserver product. In some cases, such as when an organization wishes to merge its own data with thestandard data this application provides, one of these on-premises versions is a better choice. In fact, theon-premises versions of the product allow more sophisticated analysis than their cloud siblings (today, atleast). Yet there are a number of reasons why Business Analyst Online makes sense as a cloud application.They include the following:

More approachable for infrequent or non-expert users: Many potential customers need theservices of Business Analyst Online only occasionally. Rather than make them install on-premisessoftware that they don't often use, putting this application in the cloud makes it simpler andquicker to access when needed. And because Business Analyst Online is designed to be easier touse than the on-premises version—its users aren't expected to be GIS professionals—using itonly occasionally isn't especially difficult.

Lower cost of entry: Like most cloud applications, Business Analyst Online charges its customersbased on usage. While a frequent user of the service might buy an annual subscription, acustomer is also free to buy just a single report and never use the service again. In eithercase,you pay only for what you use.

No on-premises data or software updates: All Business Analyst Online customers use the samedatabase, which is updated regularly by Esri. And because it's a cloud application, the code is alsoupdated centrally. This makes software updates simpler—they're done by Esri—with newfeatures available immediately to all of the application's users.

Better customer support: Because all Business Analyst Online customers use the same code andthe same data, Esri's support people don't need to worry about differences in configuration orinstalled data. This can potentially help them resolve customer support questions faster thanwith an on-premises product.

In some ways, GIS applications are an especially good fit for the cloud. Because they rely on large andchanging data sets, putting both this data and tools to work with the data in the cloud can make sense.Business Analyst Online provides a good example of the value this provides.

CONCLUSION

There's no denying it: Cloud computing is

here, and its effects will be widespread. In the GIS world, Esriprovides clear examples of how these new technologies can be used. Those examples include:

Using a cloud platform to provide new deployment options, such as running ArcGIS Server onAmazon Web Services.

Using a cloud platform to support Web sites that provide broadly usable GIS data and tools, asillustrated by ArcGIS.com.

Offering cloud applications that provide useful alternatives to their on-premises siblings, asshown by ArcLogistics and Business Analyst Online.

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The move to the cloud is all but certain to have an impact on your organization, both in GIS and otherareas. Why wait? The time to start understanding this shift is now.

ABOUT THE AUTHOR

David Chappell is Principal of Chappell & Associates (www.davidchappell.com) in San Francisco, California.Through his speaking, writing, and consulting,he